Snap switch



Dec. 13, 1932. F 1,891,089

SNAP SWITCH Filed May 20, 1952 His AttoY'neg;

Patented Dec. 13, 1932 UNITED STATES PATENT OFFICE,

FRITZ GRAF, OF ANNABERG, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COMPANY,

Q I A CORPORATION OF NEW YORK SNAP SWITCH Application filed May 20, 1932, Serial No. 612,585, and in Germany May 29, 1931.

' My invention relates to snap switches and more particularly to a snap switch of the rotary type.

The object of myinvention is to provide an improved snap switch'with a novel arrangement for mounting the movable contacts on the rotary member and obtaining a high contact pressure with contacts of the butt type withoutincreasing the friction opposing the movement of the rotary member.

What I consider to be novel and my invention will be better understood by reference to the following specification and appended claims when considered in connection with the accompanying drawing.

In the drawing, Fig. 1 is a sectional view of my improved switch; Fig. 2 is a plan view with the cover removed; Fig. 3 is a detail view of a portion of the operating mechanism and Fig. 4 is a detail View of a modilied form of rotary member.

Referring to Figs. 1 and 2, indicates a base of insulating material having a central cavity 11 in which the rotary member 12 is mounted. Stationary contacts 13 and 14 are secured to the base member 10 and have portions extending within the central cavity 1.1. Rotary member 12 has a member 15 with radial openings 16 and 17 connected by an annular trough 18. A bridging contact 19 consisting of a U-shaped spring member is seated in the annular trough 18 and has radial contact projections and 21 which extend. from the openings 16 and 17 respectively. To supplement the contact pressure provided by the U-shaped spring 19 spiral swings 22 and 23 are provided and located in the openings 16 and 17. The contact projections 20 and 21 are well rounded to permit them to move into engagement with the stationary contacts 13 and 14 without excessive force being required. Radial movement of contact extensions 20 and 21 is limited by engagement of the U-shaped spring member 19 with the side walls 24 of the annular trough 18 at the edges of the openings 16 and 17. Thus a high contact pressure is provided by the combinatmn of the U-shaped spring 19 and the spiral springs 22 and 23 and the walls 24 prevent the contact extensions 20 and 21 from engaging the side wall of the central cavity 11 of the base 10 when the rotary member is moved from the position shown in Fig. 2 to another position which would increase the friction opposing movement of the rotary member. To insulate the contacts froinother metal parts, a disc 2-5 is provided as shown in Fig.1 with a square opening engaginga square projec-, tion of the member 15. The rotary member is mounted on a spindle 26 j ournaledin base member 10'and resiliently connected to itby a spiral spring 27 which is connected to the spindle by a washer 28 and to the rotary member 12 by a rivet 29 which is secured to disc 25. To accomplish the stepby-step movement, an operating mechanism is provided with a plate 30 secured to member '15 by rivets 31 and 32. As best indicated in Fig. 3, plate 30 is provided with depending shoulders 33 and 34 between which a plate is adapted to slide. Plate35 has an oval opening 36 in which is seated a cam 37 secured to the spindle 26 and has a depending pin 38 which is adapted to engage the teeth of a ratchet 39. To move the rotary member 12 from one position to another, spindle 26 is rotated in a clockwise direce tion by means of handle 40. The cam 37 causes the plate 35 to slide until the pin 38 is moved out of engagement with one of the teeth of ratchet 39. At the same time the clockwise movement of the spindle 26 tensions the spring 27. When the pin 38 is thus moved out of engagement with one of the teeth of ratchet 39 the spring tension causes the rotary member to move with plate 35 until the pin engages the next tooth of ratchet 39.

In Fig. 4 is shown a modified form of rotary member consisting of two discs 40 and 41 of insulating material with a U-shaped spring 42 secured between the discs with its arms projecting through openings 43 and 44 provided in disc 41. In this modification the spring 42 is not provided with contact projections but is so formed that when in the position shown in Fig. 4 the ends of its arms engage the stationary contacts 45 and 46. The openings 43 and 44 in disc member ll serve to limit the radial movement of the arms of spring 42. The operating mechanism for this modified form of rotary memher is the same as that shown and described in connection with a preferred form of the invention and is indicated by the same numerals used to describe it heretofore.

By the arrangement of the bridging contact, as shown, a simple construction is obtained which provides a butt contact in engagement with the stationary contacts with a relatively high contact pressure and at the same time a comparatively low friction to the movement of the rotary member. In addition, this arrangement of the bridging contact is sturdy in construction and is not likely to present the operating difficulties frequently encountered in rotary switches in which the rotary contacts are in the form of polepieces with two plates that engage opposite sides of the stationary contact. These polepieces lose their resiliency after a large. number of operations and thus reduce the contact pressure and frequently cause sticking of the contacts.

Vhat I claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric switch, a base of insulating material having a central cavity, stationary contacts secured to said base and having portions extending within said cavity, a rotary member mounted in said cavity, a spindle connected to said rotary member, a spring contact seated in an annular trough in said member, the sides of the annular trough limiting the radial movement of the contact carried by the rotary member.

2. In an electric switch, a base of insulating material having a central cavity, stationary contacts secured to said base and having portions extending within said cavity, a rotary member mounted in said cavity, a spindle connected to said rotary member, a U-shaped spring carried by said rotary member and limited in the radial movement of its ends by engagement with the edge of the openings through which the arms extend from the rotary member, the ends of the U-shaped spring being adapted to engage the stationary contacts in one position of the rotary member and held out of engagement with the wall of the cavity of the base in another position.

3. In an electric switch, a base oi insulating material having a central cavity, stationary contacts secured to said base and having portions ext-ending within said cavity, a spindle connected to said rotary member, a U-shaped spring carried by said rotary member, and contacts secured to the ends of said spring projecting radially through openings in the sides of the rotary member, the radial movement of the last mentioned contacts being limited by engagement of the spring with the edge of the openings of the rotary member whereby the contacts may engage the stationary contacts in one position and are held out of engagement with the wall of the cavity of the base in another position.

4. In an electric switch, a base of insulating material having a central cavity, stationany contacts secured to said base and having portions extending within said cavity, a rotary member mounted within said cavity, a spindle connected to said rotary member, a U-shaped spring seated in an annular trough in said rotary member, contacts secured to the end of the U-shaped spring and projecting through openings of the rotary member, and spiral springs supplementing the U- shaped spring to move the contacts radially from the center of the rotary member, the radial motion of the contacts being limited by engagement of the U-shaped spring with the sides of the annular trough. i

In witness whereof, I have hereunto set my hand.

FRITZ GRAF. 

